A large international project, called Census of Marine Life, pointed out a rather surprising fact, even for scientists - apparently, there are at least 234 species that inhabit both Arctic and Antarctic waters.

The project managed to gather information on 7,500 species from the Antarctic and another 5,500 from the Arctic, with several hundred organisms that have been registered as new discoveries. The new ones are mostly simple life forms, also known as invertebrates. 

The study involved the work of over 500 polar researchers from 25 countries and was completed during the 2007 - 2008 International Polar Year.

"The textbooks have said there is less diversity at the poles than the tropics but we found astonishing richness of marine life in the Antarctic and Arctic oceans," said Victoria Wadley, a researcher from the Australian Antarctic Division who was involved in the Antarctic survey. "We are rewriting the textbooks," she added.

Among the 235 species found in both areas are six sea birds, five whale species and almost 100 species of crustaceans.

Russ Hopcroft, a plankton ecologist at the University of Alaska Fairbanks, who was involved in the Arctic survey explained that the surprise comes from the fact that there is such a great distance between the two areas, because the Arctic and the Antarctic are indeed considered similar habitats. He also mentioned that for many of the species found on both ends the research will continue, as their presence raises many evolutionary questions, especially considering the fact that there is no known connection in between.